FR3044737A1 - CONNECTION TIP FOR A FLEXIBLE CONDUIT AND ASSOCIATED MOUNTING METHOD - Google Patents

Abstract

The invention relates to a connector for connecting a flexible pipe (10) for conveying fluid. The flexible pipe (10) comprises at least one tubular sheath (20) and at least one layer (24, 25) of tensile lugs disposed externally with respect to the tubular sheath (20), the layer of armor (24, 25) comprising a plurality of filamentary armor elements (29). The tip comprises: at least one end section of each armor element; an end vault and a cap fixed on the end vault; the end vault and the cap delimiting between them a chamber; receiving of each end section, the receiving chamber being filled with a filling material. The filler material is a thermosetting polymeric resin comprising fillers.

Description

Flexible pipe connection end and method of mounting the same

The present invention relates to a connecting end of a flexible fluid transport pipe, the flexible pipe comprising at least one tubular sheath and at least one layer of tensile tack disposed externally with respect to the tubular sheath, the layer of armor comprising a plurality of filamentary armor elements, the tip comprising: - at least one end section of each armor element, - an end vault and a hood fixed on the end vault, the end vault and the cap delimiting between them a receiving chamber of each end section, the receiving chamber being filled with a filling material.

The pipe is in particular an unbonded flexible pipe for carrying hydrocarbons across an expanse of water, such as an ocean, a sea, a lake or a river, or water injection for well stimulation.

Such a flexible pipe is for example made according to the normative documents API 17J (Specification for Unbounded Flexible Pipe) and API RP 17B (Recommended Practice for Flexible Pipe) established by the American Petroleum Institute.

The pipe is generally formed of a set of concentric and superimposed layers. It is considered as "unbound" in the sense of the present invention since at least one of the layers of the pipe is able to move longitudinally relative to the adjacent layers during bending of the pipe. In particular, an unbonded pipe is a pipe devoid of binding materials connecting layers forming the pipe.

The conduit is generally disposed across an expanse of water between a bottom assembly for collecting fluid operated in the bottom of the body of water and a floating surface assembly for collecting and delivering fluid. The surface assembly may be a semi-submersible platform, an FPSO or other floating assembly.

In some cases, for the operation of fluids in deep water, the flexible pipe has a length greater than 800 m. The ends of the pipe have tips for connection to the bottom assembly and the entire surface.

These pipes undergo very high forces in axial tension, especially when the body of water in which is arranged the pipe is very deep.

In this case, the upper end connecting the pipe to the entire surface must take a very important axial tension, which can reach several hundred tons. These forces are transmitted to the tip through the layers of tensile armor extending along the pipe.

The axial tension has not only a high average value, but also permanent variations as a function of the vertical movements of the surface assembly and the pipe, under the effect of the agitation of the body of water caused by the swell or waves.

The axial tension variations can reach several tens of tons and be repeated continuously during the service life of the pipe. In 20 years, the number of cycles can reach more than 20 million.

It is therefore necessary to ensure a particularly strong attachment between the layers of tensile armor and the body of the tip. WO 2014/173874 describes a tip of the aforementioned type. The anchoring of the armor is generally ensured by the friction between the armor son and the epoxy resin cast in the chamber delimited by the vault and the hood.

However, the stresses caused by the tensile stresses of the armor cause degradation of the epoxy resin. Eventually, cracks may appear in the resin weakening the anchoring armor.

An object of the invention is to obtain a tip of a flexible pipe having an effective axial tension recovery, in which the risk of fatigue failure is greatly reduced. To this end, the invention relates to a tip of the aforementioned type, characterized in that the filling material is a thermosetting polymer resin comprising fillers. The tip according to the invention may comprise one or more of the following characteristics, taken separately or in any technically possible combination: the resin is of epoxy type, the fillers are elastomers, the fillers are chosen among styrene-butadiene (SBR), butadiene-acrylonitrile (NBR), ethylene-propylene-diene monomers (EPDM), tetrafluoroethylene-proppylene (FEPM), perfluoroelastomers (FFKM) and fluorocarbon rubber (FKM), - the fillers are thermoplastic materials, the fillers are chosen from polyethylenes (PE), high density polyethylenes (HDPE), polyethylenes of very high molar mass (UHMPE), polyamides (PA), and polytetrafluoroethylene (PTFE) the fillers are thermosetting materials, in particular polyurethanes, the fillers are chosen from single-wall nanotubes (SWNTs), multi-wall nanotubes (MWNTs) and nanofibres; s (NF), double layer nanotubes (DWNT) and nanoparticles, - nanotubes, nanofibers or nanoparticles are made of carbon, - fillers are aramid fibers, - fillers are a mixture formed of a plurality of elements among: elastomers, thermoplastic materials, thermosetting materials, single-wall nanotubes (SWNT), multi-wall nanotubes (MWNT), nanofibers (NF), double layer nanotubes (DWNT), nanoparticles and / or aramid fibers, the fillers are a mixture composed of aramid fibers and carbon nanotubes, the fillers are crosslinked or branched, and the thermosetting polymer resin has a mass concentration in filler of between 0.1% and 20%. The invention also relates to a flexible fluid transport pipe, comprising: a tubular sheath, at least one tensile armor layer disposed externally with respect to the tubular sheath, the traction armor layer comprising a plurality of filamentary armor elements, a tip as described above, mounted at the end of the tubular sheath. The invention also relates to a method of mounting a tip of a flexible fluid transport pipe, comprising the following steps: - supply of a tubular sheath, - provision of at least one armor layer of pulling on the outside of the tubular sheath, the traction armor layer comprising a plurality of filamentary armor elements, each armor element comprising an end section, - setting up a vault of end and a hood fixed on the end vault, the end vault and the hood delimiting between them a receiving chamber of the end section, - introduction of a filling material into the receiving chamber for drowning the end portion, and the filler material is a thermosetting polymeric resin comprising fillers. The invention will be better understood on reading the following description given solely by way of example, and with reference to the accompanying drawings, in which: - Figure 1 is a perspective view partially broken away of a section a flexible pipe on which is mounted a nozzle according to the invention; and FIG. 2 is a simplified schematic view, taken in section along a median axial plane, of the relevant parts of a tip of a flexible pipe according to one embodiment of the invention.

In what follows, the terms "outside" and "inside" are generally understood radially with respect to an axis A-A 'of the pipe, the term "outside" being understood as relatively more distant radially from the axis A-A 'and the term "inner" extending as relatively closer radially to the axis A-A' of the pipe.

The terms "forward" and "backward" are axially related to an axis A-A 'of the pipe, with the word "before" meaning relatively far from the middle of the pipe and more near one of its extremities, the term "rear" meaning relatively closer to the middle of the pipe and further away from one of its ends. The middle of the pipe is the point of the pipe situated equidistant from the two extremities of the latter.

A first flexible pipe 10 according to the invention is partially illustrated by FIG.

The flexible pipe 10 comprises a central section 12 illustrated in part in FIG. 1. It comprises, at each of the axial ends of the central section 12, an end tip 14 (not visible in FIG. 1), the relevant parts of which are shown. in Figure 2.

Referring to Figure 1, the pipe 10 defines a central passage 16 for circulation of a fluid, preferably a petroleum fluid. The central passage 16 extends along an axis A-A 'between the upstream end and the downstream end of the pipe 10. It opens through the endpieces 14.

The flexible pipe 10 is intended to be disposed through a body of water (not shown) in a fluid operating installation, in particular hydrocarbons. The body of water is, for example, a sea, a lake or an ocean. The depth of the water extent to the right of the fluid operating installation is for example between 500 m and 3000 m. The fluid operating installation comprises a particularly floating surface assembly and a bottom assembly (not shown) which are generally connected to each other by the flexible pipe 10.

The flexible pipe 10 is preferably an "unbonded" pipe (referred to as "unbonded").

At least two adjacent layers of the flexible pipe 10 are free to move longitudinally with respect to each other during bending of the pipe. Advantageously, all the layers of the flexible pipe are free to move relative to each other. Such conduct is for example described in the normative documents published by the American Petroleum Institute (API), API 17J, and API RP17B.

As illustrated in Figure 1, the pipe 10 defines a plurality of concentric layers around the axis A-A ', which extend continuously along the central section 12 to the ends 14 at the ends of the pipe.

According to the invention, the pipe 10 comprises at least a first tubular sheath 20 based on polymeric material advantageously constituting a pressure sheath.

The pipe 10 further comprises at least one layer of tensile armor 24, 25 arranged externally with respect to the first sheath 20.

Advantageously, and according to the desired use, the pipe 10 further comprises an internal carcass 26 disposed inside the pressure sheath 20, a pressure vault 28 interposed between the pressure sheath 20 and the layer or layers of pressure. traction armors 24, 25 and an outer sheath 30 for protecting the pipe 10.

In known manner, the pressure sheath 20 is intended to seal the fluid transported in the passage 16. It is formed of a polymer material, for example based on a polyolefin such as polyethylene, based on a polyamide such as PA11 or PA12, or based on a fluorinated polymer such as polyvinylidene fluoride (PVDF). The thickness of the pressure sheath 20 is for example between 5 mm and 20 mm.

The carcass 26, when present, is formed for example of a profiled metal strip, wound in a spiral. The turns of the strip are advantageously stapled to each other, which makes it possible to take up the radial forces of crushing.

In this example, the carcass 26 is disposed inside the pressure sheath 20. The pipe is then designated by the term "rough bore" because of the geometry of the carcass 26

Alternatively (not shown), the flexible pipe 10 is devoid of internal carcass 26, it is then designated by the term "smooth bore". The helical winding of the profiled metal strip forming the carcass 26 is short pitch, that is to say it has a helix angle of absolute value close to 90 °, typically between 75 ° and 90 °.

In this example, the pressure vault 28 is intended to take up the forces related to the pressure prevailing inside the pressure sheath 20. It is for example formed of a metallic profiled wire surrounded in a helix around the sheath 20 The profiled wire generally has a complex geometry, especially in the form of Z, T, U, K, X or I.

The pressure vault 28 is helically wound in a short pitch around the pressure sheath 20, that is to say with a helix angle of absolute value close to 90 °, typically between 75 ° and 90 °.

The flexible pipe 10 according to the invention comprises at least one armor layer 24, 25 formed of a helical winding of at least one elongate armor element 29.

In the example shown in FIG. 1, the flexible pipe 10 comprises a plurality of armor layers 24, 25, in particular an inner armor layer 24, applied to the pressure vault 28 (or to the sheath 20 when the vault 28 is absent) and an outer armor layer 25 around which outer sheath 30 is disposed.

Each layer of armor 24, 25 comprises longitudinal armor elements 29 wound with a long pitch around the axis A-A 'of the pipe.

By "wound with a long pitch" is meant that the absolute value of the helix angle is less than 60 °, and is typically between 25 ° and 55 °.

The armor elements 29 of a first layer 24 are generally wound at an opposite angle to the armor elements 29 of a second layer 25. Thus, if the winding angle of the armor elements 29 of the first layer 24 is equal to + a, a being between 25 ° and 55 °, the winding angle of the armor elements 29 of the second armor layer 25 disposed in contact with the first layer of armor 24 is for example equal to - a °.

The armor elements 29 are for example formed by metal wires, especially steel wires, or by ribbons made of composite material, for example carbon fiber-reinforced tapes.

As will be seen below, the armor elements 29 each have an end portion 32 inserted into the endpiece 14. The end portion 32 extends to a free end disposed in the endpiece 14. It advantageously has a helical or pseudo-helical trajectory of axis A-A 'in the tip 14.

The outer sheath 30 is intended to prevent the permeation of fluid from outside the flexible pipe inwardly. It is advantageously made of a polymer material, in particular based on a polyolefin, such as polyethylene, based on a polyamide, such as PA11 or PA12, or based on a fluorinated polymer such as polyvinylidene fluoride. (PVDF). The thickness of the outer sheath 30 is for example between 5 mm and 15 mm.

As illustrated in FIG. 2, each endpiece 14 has an end vault 50 and an outer connecting cover 51 projecting axially rearwards from the roof 50. The cover 51 delimits, with the end vault 50 , a chamber 52 for receiving the free ends 32 of the armor elements 29. The tip 14 further comprises a front assembly 54 sealing around the pressure sheath 20, shown schematically in Figure 2, and a rear assembly (Not shown) sealing around the outer sheath 30. The tip 14 advantageously comprises an annular member 80 for maintaining the layers of armor 24, 25 located in the rear zone of the tip.

In this example, the end vault 50 is intended to connect the pipe 10 to another connection end 14 or to terminal equipment, advantageously via an end flange (not shown).

The roof 50 has a central bore intended to receive the end of the first sheath 20 and to allow the flow of the fluid flowing through the central passage 16 towards the outside of the pipe 10.

The cover 51 has a tubular peripheral wall 70 extending around the axis A-A '. The peripheral wall 70 has a leading edge (not shown) attached to the end vault 50, radially away from the armor layers 24, 25 and a rear edge (not shown) extending axially rearwardly. beyond the end vault 50.

The cover 51 delimits the chamber 52 radially outwardly. A rear face (not visible) of the end vault 50 axially defines the chamber 52 forwards.

The volume of the chamber 52 varies according to the size of the tip. For example, for a duct of 6 ", or about 15.2 cm, the volume of the chamber 52 will be about 30L, and for a pipe of 16", about 40.6 cm, the volume of the chamber 52 will be approximately 60L The front sealing assembly 54 is advantageously located at the front of the nozzle 14, in contact with the roof 50, being offset axially forwardly relative to the annular member 80 for holding, and with respect to the rear sealing assembly.

The arch 50 is fixed by conventional fastening means, such as a screw, to the sealing assembly 54.

In known manner, it comprises a crimping front ring intended to engage the pressure sheath 20.

In the example shown in Figure 1, wherein the pipe 10 comprises a pressure vault 28, the front assembly 54 further comprises an intermediate ring of the pressure vault 28. The rear seal assembly is disposed at the rear of the annular retaining member 80. It comprises at least one crimping rear ring crimping the outer sheath 30.

Referring to Figure 2, the annular holding member 80 is disposed around the armor members 29 of the armor layer 25, at the rear portion of the tip 14. At the location of the annular holding member 80, the armor elements 29 of the armor layers 24, 25 are wound helically with the same radius of helix as they have at the central section 12. The area at which the layers of armor 24, 25 helically deviate from the axis A-A 'of the pipe to cover the front sealing assembly 54 and the end vault 50 is located between the annular member of The annular retaining member 80 is in the form of a collar, and does not contribute significantly to the recovery of tension forces. Its function is in particular to prevent the disorganization of the armor layers 24, 25 during assembly of the tip 14, as will be explained below. The tip 14 further comprises a solid filler material 82. The filling material 82 is disposed in the chamber 52 around the annular retaining member 80, the vault 50, and the end sections 32 of the armor members 29.

Advantageously, the filling material 82 completely fills the chamber 52.

According to the invention, the filling material 82 is a thermosetting polymeric resin comprising fillers.

The filler material is, for example, composed of a thermoplastic polymeric resin of polyimide (PI), polysulfone (PS), polyetheretherketone (PEEK), or polyphenylene sulfite (PPS) type.

The resin is of the epoxy type, that is to say a thermosetting polymer obtained by polymerization of epoxide monomer.

The epoxy resin has a Young's modulus between 3000 MPa and 8000 MPa and a compressive strength of between 80 MPa and 130 MPa.

The resin is preferably a thermosetting polymer, having in particular a heat resistance, mechanical properties, chemical resistance and a better adhesion of armors compared to those of thermoplastics.

The thermosetting polymeric resin has a mass concentration in filler of between 0.1 and 20%, preferably between 0.1 and 4%.

The concentration varies according to the nature of the charges and depending on the composition of the resin, especially hardeners.

For a mass concentration in charges greater than 0.1%, the toughness and the resistance to compression, traction and shearing of the resin increase.

For a mass concentration in charges greater than 20%, the resin is more fragile and the viscosity of the resin is too high.

The charges are in solid or liquid form, and preferably in solid form. They are advantageously crosslinked or branched.

In a first embodiment, the charges are elastomers. The fillers are selected from styrene-butadiene (SBR), butadiene-acrylonitrile (NBR), ethylene-propylene-diene monomers (EPDM), tetrafluoroethylene-proppylene (FEPM), perfluoroelastomers (FFKM) and fluorocarbon rubber ( FKM).

In a second embodiment, the fillers are thermoplastic materials. The fillers are chosen from polyethylenes (PE), high density polyethylenes (HDPE), polyethylenes of very high molar mass (UHMPE), polyamides (PA), and polytetrafluoroethylene (PTFE).

Alternatively, the fillers are thermosetting materials, for example, polyurethanes.

Alternatively, the fillers are chosen from single-wall nanotubes (SWNT), multi-wall nanotubes (MWNT), double-leaf nanotubes (DWNT), nanofibers (NF) and nanoparticles.

Nanoparticles are particles of graphite or graphene.

Nanotubes, nanofibers or nanoparticles are carbon.

The multifilament nanotubes (MWNT) are nanotubes having a diameter of between 8 nm and 50 nm and a length of between 1 μm and 50 μm.

In another embodiment, the fillers are aramid fibers, such as para aramid fibers, Kevlar® type, or para aramid copolymers.

The aramid fibers have a diameter of between 150 μm and 190 μm and a length of between 0.25 mm and 6 mm.

Alternatively, the fillers are a combination of the above-mentioned compounds. The fillers are a mixture formed of a plurality of elements among: elastomers, thermoplastic materials, thermosetting materials, single-wall nanotubes (SWNT), multi-wall nanotubes (MWNT), nanofibers (NF), double-layer nanotubes (DWNT), nanoparticles and / or aramid fibers.

The fillers are, for example, a mixture composed of aramid fibers and carbon nanotubes.

The material 82 substantially completely fills the chamber 52. It is preferably fluidly injected into the chamber 52 and solidifies therein, by binding the end sections 32 of the armor elements 29 to the vault 50 and / or hood 51. The assembly of the nozzle 14 according to the invention is carried out as follows.

Initially, the various layers of the pipe 10 are cut to the right length to reveal, on the roof 28, a free end section 32 of each armor element 29 of the armor layers 24, 25.

Then, the annular member 80 in an expanded configuration is introduced around the armor layer 25, before being tightened around it.

This being done, the end sections 32 of the armor members 29 are folded rearwardly around the annular retaining member 80. The end vault 50 and the front sealing assembly 54 are then placed in place.

Then, each end portion 32 of the inner armor layer 24 is unfolded forward.

The end sections 32 are spaced apart by a distance of the order of a few millimeters.

The end sections 32 have wave-shaped ends or hooks which promote their anchoring within the filling material.

The end portions 32 optionally comprise a coating, for example an epoxy resin, for limiting the wear of the end sections.

The end sections 32 comprise spacers rubber or elastomer, for example, which allows in particular to promote the contact surface between the sections and the resin.

The cover 51 is then put in place and fixed to the roof 50.

The cover 51 is spaced from the end sections 32 by a distance of between 5 mm and 16 mm. The rear sealing assembly is then put in place and is attached to the hood 51.

The filling material 82 is then introduced into the chamber 52, advantageously in fluid form. The filling material 82 is injected under pressure into the chamber 52 through orifices placed within the cover 51. There is generally between 4 and 6 orifices with a diameter substantially equal to 14 mm.

The material 82 fills the chamber 52 and solidifies between the roof 50 and the cover 51 around the end sections 32 of the armor elements 29. The epoxy resin solidifies at room temperature, corresponding to the temperature inside the the mouthpiece, and atmospheric pressure. When the temperature is below 5 ° C, insulation is wrapped around the tip.

The solidification time is of the order of a few hours, more particularly from 3h to 6h.

The end sections 32 are then embedded in the filling material 82.

In operation, when the tip 14 is connected to another endpiece or to a surface assembly, the axial tension transmitted by the armor layers 24, 25 resulting from the weight of the pipe 10 is taken up by the sections 32 embedded in the filling material 82.

The presence of fillers in the resin of the filler material is intended to improve the mechanical properties of the resin, including shear strength, tensile strength, compressive strength and fracture toughness.

In fact, the addition of 0.5% of MWCT makes it possible to improve the properties of a resin with an increase in the tenacity of 87%, an increase in the elongation at break of 94% and an increase in the tensile strength of 25%.

There is also an increase in the glass transition temperature.

This prevents or limits the propagation of cracks in the resin. Better anchoring of the armor is ensured within the resin.

Claims (16)

1, - An end (14) for connecting a flexible pipe (10) for conveying fluid, the flexible pipe (10) comprising at least one tubular sheath (20) and at least one layer (24, 25) of tack traction device disposed externally with respect to the tubular sheath (20), the armor layer (24, 25) comprising a plurality of filamentary armor elements (29), the endpiece comprising: at least one section of armor end (32) of each armor element, - an end vault (50) and a hood (51) fixed on the end vault, the end vault (50) and the hood (51) delimiting between them a receiving chamber (52) of each end section, the receiving chamber being filled with a filling material (82), characterized in that the filling material (82) is a thermosetting polymeric resin comprising fillers . 2, - connection tip according to claim 1, characterized in that the resin is of the epoxy type. 3. - Connection end according to claim 1 or 2, characterized in that the charges are elastomers. 4, - connection tip according to claim 3, characterized in that the fillers are selected from styrene-butadiene (SBR), butadiene-acrylonitrile (NBR), ethylene-propylene-diene monomers (EPDM), tetrafluoroethylene- proppylene (FEPM), perfluoroelastomers (FFKM) and fluorocarbon rubber (FKM). 5. - Connecting tip according to claim 1 or 2, characterized in that the charges are thermoplastic materials. 6. - Connection end piece according to claim 5, characterized in that the fillers are chosen from polyethylenes (PE), high density polyethylenes (HDPE), polyethylenes of very high molecular weight (UHMPE), polyamides (PA) , and polytetrafluoroethylene (PTFE). 7. - Connection end according to claim 1 or 2, characterized in that the charges are thermosetting materials, including polyurethanes. 8. - Connection end according to claim 1 or 2, characterized in that the charges are selected from single-wall nanotubes (SWNT), multifilament nanotubes (MWNT), nanofibers (NF), double layer nanotubes (DWNT) and nanoparticles. 9. - Connecting tip according to claim 8, characterized in that the nanotubes, nanofibers or nanoparticles are carbon. 10. - Connection end according to claim 1 or 2, characterized in that the charges are aramid fibers. 11. - connector end according to claim 1 or 2, characterized in that the charges are a mixture formed of a plurality of elements among: elastomers, thermoplastic materials, thermosetting materials, single-wall nanotubes (SWNT), multifilament nanotubes (MWNT), nanofibers (NF), double layer nanotubes (DWNT), nanoparticles and / or aramid fibers. 12. Connection end according to claim 11, characterized in that the charges are a mixture of aramid fibers and carbon nanotubes. 13. - Connection piece according to any one of the preceding claims, characterized in that the charges are crosslinked or branched. 14. - Connection end piece according to any one of the preceding claims, characterized in that the thermosetting polymer resin has a mass concentration in charges of between 0.1% and 20%. 15. - Conduit (10) flexible fluid transport, comprising: - a tubular sheath (20), - at least one layer of armor (24, 25) traction disposed externally relative to the tubular sheath (20), the tensile armor layer (24, 25) comprising a plurality of filamentary armor members (29), - a tip (14) according to any one of the preceding claims, mounted at the end of the tubular sleeve (20). 16. A method of mounting a tip (14) of a pipe (10) flexible fluid transport, comprising the following steps: - supply of a tubular sheath (20) - provision of at least one layer traction armor (24, 25) on the outside of the tubular sheath (20), the pull armor layer (24, 25) comprising a plurality of filiform armor elements (29), each element armor (29) comprising an end section (32), - setting up an end vault (50) and a cover (51) fixed on the end vault (50), the end vault (50) and the cover (51) delimiting between them a receiving chamber (52) of the end section (32), - introducing a filler material (82) into the receiving chamber (52) ) for embedding the end portion (32), characterized in that the filler material (82) is a thermosetting polymeric resin comprising fillers.